diff mbox series

[v2] tools/build: Add clang cross-compilation flags to feature detection

Message ID 20231102103252.247147-1-bjorn@kernel.org (mailing list archive)
State Not Applicable
Headers show
Series [v2] tools/build: Add clang cross-compilation flags to feature detection | expand

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Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Björn Töpel Nov. 2, 2023, 10:32 a.m. UTC 
From: Björn Töpel <bjorn@rivosinc.com>

When a tool cross-build has LLVM=1 set, the clang cross-compilation
flags are not passed to the feature detection build system. This
results in the host's features are detected instead of the targets.

E.g, triggering a cross-build of bpftool:

  cd tools/bpf/bpftool
  make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1

would report the host's, and not the target's features.

Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
feature detection makefile.

Fixes: cebdb7374577 ("tools: Help cross-building with clang")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
---
 tools/build/Makefile.feature |  2 +-
 tools/build/feature/Makefile | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)


base-commit: 21e80f3841c01aeaf32d7aee7bbc87b3db1aa0c6

Comments

Jiri Olsa Nov. 2, 2023, 12:30 p.m. UTC | #1 
On Thu, Nov 02, 2023 at 11:32:52AM +0100, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> When a tool cross-build has LLVM=1 set, the clang cross-compilation
> flags are not passed to the feature detection build system. This
> results in the host's features are detected instead of the targets.
> 
> E.g, triggering a cross-build of bpftool:
> 
>   cd tools/bpf/bpftool
>   make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1
> 
> would report the host's, and not the target's features.
> 
> Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
> feature detection makefile.
> 
> Fixes: cebdb7374577 ("tools: Help cross-building with clang")
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
>  tools/build/Makefile.feature |  2 +-
>  tools/build/feature/Makefile | 12 ++++++------
>  2 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
> index 934e2777a2db..25b009a6c05f 100644
> --- a/tools/build/Makefile.feature
> +++ b/tools/build/Makefile.feature
> @@ -8,7 +8,7 @@ endif
>  
>  feature_check = $(eval $(feature_check_code))
>  define feature_check_code
> -  feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
> +  feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" CLANG_CROSS_FLAGS="$(CLANG_CROSS_FLAGS)" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
>  endef
>  
>  feature_set = $(eval $(feature_set_code))
> diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
> index dad79ede4e0a..c4458345e564 100644
> --- a/tools/build/feature/Makefile
> +++ b/tools/build/feature/Makefile
> @@ -84,12 +84,12 @@ PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
>  
>  all: $(FILES)
>  
> -__BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
> +__BUILD = $(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
>    BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
>    BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
>    BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap
>  
> -__BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
> +__BUILDXX = $(CXX) $(CXXFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
>    BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
>  
>  ###############################
> @@ -259,10 +259,10 @@ $(OUTPUT)test-reallocarray.bin:
>  	$(BUILD)
>  
>  $(OUTPUT)test-libbfd-liberty.bin:
> -	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
> +	$(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
>  
>  $(OUTPUT)test-libbfd-liberty-z.bin:
> -	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
> +	$(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
>  
>  $(OUTPUT)test-cplus-demangle.bin:
>  	$(BUILD) -liberty
> @@ -283,10 +283,10 @@ $(OUTPUT)test-libbabeltrace.bin:
>  	$(BUILD) # -lbabeltrace provided by $(FEATURE_CHECK_LDFLAGS-libbabeltrace)
>  
>  $(OUTPUT)test-compile-32.bin:
> -	$(CC) -m32 -o $@ test-compile.c
> +	$(CC) $(CLANG_CROSS_FLAGS) -m32 -o $@ test-compile.c
>  
>  $(OUTPUT)test-compile-x32.bin:
> -	$(CC) -mx32 -o $@ test-compile.c
> +	$(CC) $(CLANG_CROSS_FLAGS) -mx32 -o $@ test-compile.c
>  
>  $(OUTPUT)test-zlib.bin:
>  	$(BUILD) -lz
> 
> base-commit: 21e80f3841c01aeaf32d7aee7bbc87b3db1aa0c6
> -- 
> 2.40.1
>
Björn Töpel April 26, 2024, 10:31 a.m. UTC | #2 
Jiri Olsa <olsajiri@gmail.com> writes:

> On Thu, Nov 02, 2023 at 11:32:52AM +0100, Björn Töpel wrote:
>> From: Björn Töpel <bjorn@rivosinc.com>
>> 
>> When a tool cross-build has LLVM=1 set, the clang cross-compilation
>> flags are not passed to the feature detection build system. This
>> results in the host's features are detected instead of the targets.
>> 
>> E.g, triggering a cross-build of bpftool:
>> 
>>   cd tools/bpf/bpftool
>>   make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1
>> 
>> would report the host's, and not the target's features.
>> 
>> Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
>> feature detection makefile.
>> 
>> Fixes: cebdb7374577 ("tools: Help cross-building with clang")
>> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
>
> Acked-by: Jiri Olsa <jolsa@kernel.org>

Waking up the dead!

Arnaldo, Jean-Philippe: I'm still stung by what this patch fixes. LMK
what you need from me/this patch to pick it up.


Cheers,
Björn
Jean-Philippe Brucker April 29, 2024, 5:11 p.m. UTC | #3 
On Fri, Apr 26, 2024 at 12:31:17PM +0200, Björn Töpel wrote:
> Jiri Olsa <olsajiri@gmail.com> writes:
> 
> > On Thu, Nov 02, 2023 at 11:32:52AM +0100, Björn Töpel wrote:
> >> From: Björn Töpel <bjorn@rivosinc.com>
> >> 
> >> When a tool cross-build has LLVM=1 set, the clang cross-compilation
> >> flags are not passed to the feature detection build system. This
> >> results in the host's features are detected instead of the targets.
> >> 
> >> E.g, triggering a cross-build of bpftool:
> >> 
> >>   cd tools/bpf/bpftool
> >>   make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1
> >> 
> >> would report the host's, and not the target's features.
> >> 
> >> Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
> >> feature detection makefile.
> >> 
> >> Fixes: cebdb7374577 ("tools: Help cross-building with clang")
> >> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
> >
> > Acked-by: Jiri Olsa <jolsa@kernel.org>
> 
> Waking up the dead!
> 
> Arnaldo, Jean-Philippe: I'm still stung by what this patch fixes. LMK
> what you need from me/this patch to pick it up.

I guess the problem is these files don't have a specific tree. Since you
mention BPF maybe it should go through the BPF tree, in which case you
could resend to the tools/bpf maintainers (and "PATCH bpf" subject prefix)

FWIW the change looks good to me:

Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Björn Töpel May 2, 2024, 9:07 p.m. UTC | #4 
Jean-Philippe Brucker <jean-philippe@linaro.org> writes:

> On Fri, Apr 26, 2024 at 12:31:17PM +0200, Björn Töpel wrote:
>> Jiri Olsa <olsajiri@gmail.com> writes:
>> 
>> > On Thu, Nov 02, 2023 at 11:32:52AM +0100, Björn Töpel wrote:
>> >> From: Björn Töpel <bjorn@rivosinc.com>
>> >> 
>> >> When a tool cross-build has LLVM=1 set, the clang cross-compilation
>> >> flags are not passed to the feature detection build system. This
>> >> results in the host's features are detected instead of the targets.
>> >> 
>> >> E.g, triggering a cross-build of bpftool:
>> >> 
>> >>   cd tools/bpf/bpftool
>> >>   make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1
>> >> 
>> >> would report the host's, and not the target's features.
>> >> 
>> >> Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
>> >> feature detection makefile.
>> >> 
>> >> Fixes: cebdb7374577 ("tools: Help cross-building with clang")
>> >> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
>> >
>> > Acked-by: Jiri Olsa <jolsa@kernel.org>
>> 
>> Waking up the dead!
>> 
>> Arnaldo, Jean-Philippe: I'm still stung by what this patch fixes. LMK
>> what you need from me/this patch to pick it up.
>
> I guess the problem is these files don't have a specific tree. Since you
> mention BPF maybe it should go through the BPF tree, in which case you
> could resend to the tools/bpf maintainers (and "PATCH bpf" subject prefix)
>
> FWIW the change looks good to me:
>
> Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

Thanks for the review. Yes, maybe it's a orphan files issue! It does
seem a bit weird to route it via BPF, since it's just a regular
cross-build fix -- Not directly related to BPF. Regardless; I'll do a
respin targetted at *some* tree. ;-)


Björn
diff mbox series

Patch

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 934e2777a2db..25b009a6c05f 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -8,7 +8,7 @@  endif
 
 feature_check = $(eval $(feature_check_code))
 define feature_check_code
-  feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
+  feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" CLANG_CROSS_FLAGS="$(CLANG_CROSS_FLAGS)" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
 endef
 
 feature_set = $(eval $(feature_set_code))
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index dad79ede4e0a..c4458345e564 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -84,12 +84,12 @@  PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
 
 all: $(FILES)
 
-__BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
+__BUILD = $(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
   BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
   BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
   BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap
 
-__BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
+__BUILDXX = $(CXX) $(CXXFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
   BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
 
 ###############################
@@ -259,10 +259,10 @@  $(OUTPUT)test-reallocarray.bin:
 	$(BUILD)
 
 $(OUTPUT)test-libbfd-liberty.bin:
-	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
+	$(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
 
 $(OUTPUT)test-libbfd-liberty-z.bin:
-	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
+	$(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
 
 $(OUTPUT)test-cplus-demangle.bin:
 	$(BUILD) -liberty
@@ -283,10 +283,10 @@  $(OUTPUT)test-libbabeltrace.bin:
 	$(BUILD) # -lbabeltrace provided by $(FEATURE_CHECK_LDFLAGS-libbabeltrace)
 
 $(OUTPUT)test-compile-32.bin:
-	$(CC) -m32 -o $@ test-compile.c
+	$(CC) $(CLANG_CROSS_FLAGS) -m32 -o $@ test-compile.c
 
 $(OUTPUT)test-compile-x32.bin:
-	$(CC) -mx32 -o $@ test-compile.c
+	$(CC) $(CLANG_CROSS_FLAGS) -mx32 -o $@ test-compile.c
 
 $(OUTPUT)test-zlib.bin:
 	$(BUILD) -lz